Instability phenomena in microcrystalline silicon films

Abstract

Microcrystalline silicon (μc-Si:H) for solar cell applications is investigated with respect to the material stability upon treatment of the material in various environments, followed by annealing. The material can be separated into two groups: (i) material with high crystalline volume fractions and pronounced porosity which is susceptible to in-diffusion of atmospheric gases, which, through adsorption or oxidation affect the electronic properties and (ii) compact material with high or low crystalline volume fractions which show considerably less or no influence of treatment in atmospheric gases. We report the investigation of such effects on the stability of μc-Si:H films prepared by plasma enhanced chemical vapour deposition and hot wire chemical vapour deposition.